Add header

This adds a header across the top of the whole app and adds a logo/mark.

## After:

![screen shot 2013-11-06 at 12 23 16 am](https://f.cloud.github.com/assets/173/1480265/70065118-46a4-11e3-8425-21f39fb8bce8.png)

## Before:

![screen shot 2013-11-06 at 12 30 38 am](https://f.cloud.github.com/assets/173/1480267/a0ddc67c-46a4-11e3-8011-19104e65970d.png)